The Resistance Movement: Cancer, like infectious disease, also develops resistance to the drugs used to treat it

Infectious Disease is not alone in its resistance to therapeutic drugs: cancer behaves much the same way. For instance, when we say that a chemotherapy patient relapses, what’s happening is that the cancer cells have developed resistance to the chemo drug, thus rendering it useless, allowing the cancer cells to grow back.

The relationship between antibiotic therapy and chemotherapy dates back to the origins of chemotherapy, some 70 years ago. Sid Mukerjee, M.D., in his 2011 Pulitzer prize-winning book, The Emperor of All Maladies – A Biography of Cancer explains that in the late 1940s, the idea of chemotherapy – a drug that could cure cancer – began to take hold. The timing was no accident. This was on the heels of the birth of the Antibiotic Age that began with the widespread use of penicillin by American and British Forces during WW ll. The use of the drug was so successful that it spawned the idea in oncologists to look for “a penicillin for cancer.”

Cancer cells mutate quickly in response to chemotherapy, thus a never-ending “cat-and-mouse game” between the two. And so “we are forced to keep running merely to keep still.”

Cancer cells mutate quickly in response to chemotherapy, thus it’s a never-ending “cat-and-mouse game” between the two. 

Cancer cells mutate quickly in response to chemotherapy, thus a never-ending “cat-and-mouse game” between the two. “This is our predicament with cancer: we are forced to keep running merely to keep still.”

So it came as little surprise that the first ant-cancer drug was, in fact, an antibiotic – actinomycin D – that was repurposed to act as an anti-cancer agent. This was the summer of 1955 and the drug worked – to a degree. It caused remissions that lasted months – but only months – in a rare form of kidney cancer in children.

More drugs soon followed that treated other cancers. However, not only did the problem of resistance always emerge, something even worse happened: In one trial, for example, people treated with multi-drug chemotherapy for Hodgkin’s disease would relapse; not with Hodgkin’s disease, but with a second and different cancer – typically an aggressive drug resistant leukemia – caused by the chemotherapy.

The lesson soon leaned by the cancer community was the one already learned by the infectious disease community: the cell – whether it’s a human cell, a cancer cell, or a bacterial cell such as MRSA, – is built to adapt and survive, even when attacked by poisons such as antibiotics or chemotherapeutics.

The chart on drug resistance is instructive. While it focuses on bacterial mutation and resistance, it works the same way with cancer cell mutation and the resulting resistance to chemotherapy:

drug resistance

Author, researcher, and infectious disease specialist Brad Spellberg, M.D., in an interview with NPR, “Bacterial Infections Defy Treatment,” echo’s Mukerjee’s sentiments on the “cat-and-mouse game” of drug resistance. He phrases it as a constant trade-off between “our wits versus their genes”:

So let’s quote Joshua Lederberg, Nobel laureate, who in 2000 wrote that the future of humanity and microbes would likely evolve as episodes of our wits versus their genes.

This is what bacteria [e.g. MRSA] do. They’re just being bacteria. They become resistant to stuff, they adapt. We have to accept that’s never going to stop. No matter how perfect our stewardship is, no matter how prefect our infection control is, they’re always going to adapt. So, yes, we are never going to win in the end. But … we know steps that we can [adopt] to get back ahead in the race.




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